The Ideal Flow Network (IFN) method is a new method that can be used to estimate the congestion index. The IFN method is different from the traditional traffic assign methods because it does not require an OD-Matrix in its calculations. In using the IFN method, the road network must be a strongly connected network, and the number of outgoing currents must be the same as that of incoming ones. This causes IFN to be irreducible and premagic. In this study, the IFN method will be used to estimate the congestion rate of 300 major cities in the world based on GDP, population, and area. The results achieved will be presented as a ranking as ranking cities using the IFN method has never been done in the world. In addition, congestion figures are compared with various indicators to find out the relationship between congestion figures and these indicators. The study results show that the congestion rate is almost unrelated to a city’s GDP, population, and area. The results are then uploaded to the website so the world can learn the IFN method as a tool for estimating congestion figures.